To put this in context, Janet Street-Porter's acclaimed Network 7 youth programme on Channel 4 came more than a year later.

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Across the Line showcases the best alternative music from Northern Ireland and the Republic - including Tim Wheeler's Ash

An early champion of new local sounds, offering many young bands their first radio play and exposure to an audience that could propel them to success, The Bottom Line also dealt with hard-hitting social issues like drugs and punishment beatings.

The programme was originally broadcast on BBC Radio Five as well as Radio Ulster and despite a brief break and a name change, 30 years later the ethos remains the same - to showcase the best emerging and established alternative music from Northern Ireland and the Republic of Ireland.

Sinead O'Connor and Jerusalem

The show's first presenter, Mike Edgar (now head of entertainment at BBC Northern Ireland) still gets excited, three decades later, when trying to convey its significance.

"There was literally nothing else out there that was similar, which put us in a really privileged position in that we were able to develop strong relationships with big artists who respected what we were doing for new music, promoting up-and-coming talent," he said. "Many of them got their first break with us too."

"Sinead O'Connor did her first BBC session with us - she sang Jerusalem, it was amazing.

"And I remember Gary Lightbody telling me how he would get his dad to drive him down to drop a demo cassette off.

"We had the Manic Street Preachers and David Gray sending us demos as well - we felt so lucky to be doing what we were doing and discovering such talent, while at the same time bringing in the big names like BB King, who came back and back - he was just fantastic."

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Snow Patrol's Gary Lightbody would get his dad to drive him to the studio to drop off demo cassettes, said Mike Edgar

When U2 performed a special concert to celebrate the Good Friday Agreement, the programme - by then known as Across the Line - was the only media outlet to get an extended, exclusive interview.

"There were international press standing outside the Waterfront Hall, waiting for a sound bite from Bono, and there he was with us backstage, giving us half an hour of his time," said Mr Edgar.

Sock hats and star presenters

Fast-forward to September 2016 and the 30-year-old programme is aging well.

The latter, 20-year-old artist's performance will be her penultimate of a two-year tour, and she is glad it is happening in Belfast.

"I've never played in the Ulster Hall before so it's going to be pretty special," said Soak.

"Before I even performed on Across the Line they were the first to play my songs and I'll always remember that feeling of hearing myself on the radio for the first time.

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Cashier No 9

"On my first performance I was wearing this really stupid sort of sock hat and was so nervous, but (presenter) Rigsy really put me at ease.

"I always listen to Across the Line now to hear new music from Northern Ireland - anyone who is played on Radio 1 has almost definitely been played on Across the Line before that. It's an incredible platform for people like me."

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ATL presenters Rigsy and Stuart Bailie are hosting a 30-year anniversary event for the show

Over the past year in the run up to the anniversary, the programme's frontman Rigsy and Stuart Bailie have been revisiting ATL's back catalogue of live performances and interviews and looking back at some historical musical moments in Northern Ireland.

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Conor O'Brien of the Villagers will be among the musicians at the Ulster Hall on Monday night

But it is not just the performers who have moved on to high-profile careers in music and broadcasting - past presenters included Colin Murray and Radio 1's Phil Taggart and even Radiohead.

Hot Press editor Niall Stokes has been a fan of the programme since the '80s.

"There is no over-stating the importance of Across The Line to Irish music," he said.

"It is really vital for the genuinely committed and creative Irish artists and bands to have a platform on radio where their music can be heard - and heard consistently.

"Across The Line has provided that platform in a unique and wonderfully supportive way, over a sustained period. In the process the programme has successfully helped to open audiences up to brilliant new artists - also enabling musicians to forge careers that might otherwise have foundered.

"The entire Irish music community owes everyone involved in the programme - not least its founder and guiding spirit Mike Edgar - a huge debt of gratitude. Long may it run."